Medium · CVSS 6.8CVE-2026-57843

NetBSD mm_open() PK_KMEM Flag Kernel Pointer Information DisclosureCVE-2026-57843

Answer in brief

CVE-2026-57843 records a Medium severity (CVSS 6.8) vulnerability in NetBSD mm_open() PK_KMEM Flag Kernel Pointer Information Disclosure. The current sources do not mark it as known exploited. The current feed maps The NetBSD Foundation/NetBSD (generic), The NetBSD Foundation/NetBSD (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Oct 1, 2026Source checked Oct 26, 2026First seen by HOL Sep 11, 2026Material review Oct 1, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps The NetBSD Foundation/NetBSD (generic), The NetBSD Foundation/NetBSD (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
The NetBSD Foundation/NetBSDgeneric	>=9.0 <9.5 \|\| >=10.0 <=10.1	9.5
The NetBSD Foundation/NetBSDgeneric	>=9.0 <9.5 \|\| 10.0	9.5

Recommended response

Check inventory. Check lockfiles and deployed manifests for The NetBSD Foundation/NetBSD, The NetBSD Foundation/NetBSD.
Review the reported fix. Update The NetBSD Foundation/NetBSD to 9.5; The NetBSD Foundation/NetBSD to 9.5 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source description

NetBSD contains an information disclosure vulnerability in mm_open() within sys/dev/mm.c that allows unprivileged local users to obtain real kernel virtual addresses by opening world-accessible devices such as /dev/null or /dev/zero, which incorrectly receive the PK_KMEM process flag. Attackers can exploit this misconfigured flag to bypass the CANSEE_KPTR obfuscation mechanism and read kernel virtual addresses for sensitive kernel structures including struct proc, kauth_cred, filedesc, and vmspace via sysctl KERN_PROC queries.

Quoted source text, attributed separately from HOL analysis.